Authorities will conduct a forensic examination of Philip D. Chism’s shattered cellphone in an effort to determine whether the teenager took images when he allegedly raped and killed Danvers High School teacher Colleen Ritzer in October.
In a search warrant affidavit obtained Monday, investigators also said that Chism, in an interview with police, had “admitted murdering Colleen Ritzer” but denied “having committed a sexual assault or any sexual touching of Ritzer whatsoever.”
Chism was 14 when he allegedly attacked Ritzer, 24, a math teacher, inside a second-floor bathroom at Danvers High on Oct. 22 and then used a recycling bin to haul her to the woods next to the school, where her body was found early on Oct. 23.
Chism has pleaded not guilty to a first-degree murder charge and one count of aggravated rape and is being held without bail. He is to be arraigned Thursday in Essex Superior Court on a second count of aggravated rape filed last week after authorities allegedly matched biological evidence recovered from Ritzer to Chism through DNA testing.
A Ritzer family spokesman said Monday the family had no comment on the new charge.
The affidavit seeking permission to look into Chism’s cellphone was filed in Essex Superior Court last week. In it, State Police Detective Steven J. Buccheri outlined the state’s case and said investigators wanted to examine the cellphone because they have reason to believe Chism planned the crime, and “perpetrators who conduct such planning” sometimes do research on the Internet or make notes of their planning in notes or text messages.
Buccheri wrote that Chism told police after his arrest that he had destroyed his cellphone and an iPhone he stole from Ritzer so police could not use GPS to track him. Chism then allegedly drew a map of where he had dumped both cellphones; police found them near the Hollywood Hits movie theater he went to after Ritzer’s death.
Buccheri said the reason Chism gave for destroying the phones didn’t ring true to investigators. “Chism’s explanation for attempting to destroy his phone, along with other minimizations and denials in his interview, seems doubtful,” he wrote, noting that “it is widely understood that GPS may be disabled without the destruction of the phone itself.’’
Buccheri wrote that “it is not unusual for individuals involved in homicides, particularly sexually violent homicides, to memorialize their victims’ deaths through photographic, audio, and or video media for further humiliation of the victim or later viewing, for guilt relief or for enjoyment.”
Given “the sexual offender’s proclivity to memorialize their crimes, it is likely that he destroyed the phone in order to hid [sic] incriminating evidence on it, including but not limited to evidence of his planning, motive, and any memorialization of his crime,” Buccheri wrote.
The affidavit said Chism, who is now 15, had admitted to killing the teacher in an interview with police while his mother was present. The admission came before Ritzer’s body had been found.
Police applied for the search warrant Friday and were given approval to take the phone to the State Police laboratory in Maynard for a forensic examination. The court records do not say if the testing has been completed, nor do they indicate what, if anything, was found.
A spokeswoman for Essex District Attorney Jonathan Blodgett declined to comment on the search of the cellphone.
“I cannot comment on any specific evidence in the case nor can I characterize where we are in terms of gathering that evidence,’’ Carrie Kimball Monahan said in a telephone interview Monday. “All evidence will be presented in court, not in the newspaper.’’
Denise Regan, Chism’s defense attorney from the Committee for Public Counsel Services office in Salem, did not immediately return a phone message seeking comment.
Follow her on Twitter @GlobeKMcCabe. John R. Ellement can be reached at email@example.com. Follow him on Twitter @JREbosglobe.